This invention relates to the production of envelope blanks by the method generally known as "fly cutting".
In a known method of fly cutting, a continuous web of paper is advanced in a generally horizontal path between two pairs of rotary cutters or knives. The cutters of each pair are located on opposite sides of the web at different positions along the line of travel of the web. The knives rotate to pass from top to bottom through the web as it advances to produce the cut out portions extending inwards from each of the side edges of the web.
An object of the present invention is to provide an improved way of producing envelope blanks by fly cutting.